INDIUM DOPING OF CDTE GROWN BY MOLECULAR-BEAM EPITAXY

We report on n-type indium doping of CdTe films grown by molecular beam epitaxy on (001) GaAs substrates. By adjusting the flux of In atoms we can precisely control the carrier concentration over three orders of magnitude - from 8 x 10(14) up to 1.3 x 10(18) cm(-3). In agreement with earlier reports we confirmed that Cd overpressure plays an important role in the doping process. The doping appears to be most effective for Cd/Te pressure ratio of 1.5. For this value of Cd/Te pressure ratio essentially 100% efficiency of doping is achieved at low In concentrations (< 10(18) cm(-3)). At higher In concentrations acceptor impurities compensate shallow donors limiting the concentration of free carriers.